Good clinical practice in orthokeratology

Pauline Cho *, Sin Wan Cheung, John Mountford, Peter White

School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China

Abstract

Overnight orthokeratology is becoming more and more popular especially in the Asia-Pacific region where the treatment is primarily used

for myopic control in young children. Risk of complications in contact lens wear increases during overnight wear and may further increase

when the treatment is used on children. The aim of this paper is to provide a comprehensive guideline for practitioners to improve their

orthokeratology practice and minimize unnecessary or preventable complications.

The fundamental requirement for starting an orthokeratology practice is to have proper education in the area and to equip the practice

appropriately. Overnight trial fitting is recommended to confirm the physiological response prior to commencement of the treatment.

Practitioners should provide adequate information, both oral and written, to patients before and after the commencement of treatment to avoid

any legal dilemmas and to improve patients’ compliance. Costs for the treatment should be transparent and provision of an emergency contact

number is a must. Patients should be regularly recalled for aftercare visits and all communication with patients should be properly

documented. In this paper, patient selection and the clinical procedures were discussed and a standard of practice in orthokeratology proposed.

We believe that the key to providing a safe orthokeratology practice is to continually update knowledge in the field, and to practice to the

highest professional standards.

# 2007 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Keywords: Orthokeratology; Guidelines; Overnight wear; Standard of care

www.elsevier.com/locate/clae

Contact Lens & Anterior Eye 31 (2008) 17–28

1. Introduction

Optometry is a primary care health profession, yet it has

the unique dichotomy of providing a professional service as

well as supplying the required optical aids at a profit. It

would therefore be prudent to open this discussion with

reference to the ‘‘rights’’ of ‘‘patients’’ compared to those of

‘‘customers’’. In terms of the optometrist’s professional

relationship with the patient, this is governed to a large

degree by whether the relationship is contractual or not.

With respect to orthokeratology (ortho-k), legal responsi-

bility is usually established under tort law, whereby the

practitioner’s duty of care, legal obligation, or standard of

care is not necessarily dictated by a formal, written

agreement between both parties, but is reflected by the

common law system. Any sub-standard practice may result

in a civil claim for compensation arising from professional

negligence. However, some practitioners may prefer to

* Corresponding author.

E-mail address: sopaulin@polyu.edu.hk (P. Cho).

1367-0484/$ – see front matter # 2007 British Contact Lens Association. Publi

doi:10.1016/j.clae.2007.07.003

establish a contractual relationship with their patients, in

terms of services and goods provided, and this in turn would

be governed by contract law [1]. In this case, the patient

would appear more like a customer. Nevertheless, whatever

the relationship, the legal responsibilities of the optometrist

are set in law and cannot be ignored, as the law protects the

patient/customer in both cases.

Overnight wear ortho-k is becoming increasingly popular

for myopic reduction in many parts of the world [2]. Recent

studies have shown the treatment to be effective for slowing

the progress of myopia [3,4] and this is likely to increase the

use of ortho-k. Modern ortho-k involves the use of RGP

lenses worn on an overnight wear basis. The advantages of

this modality are less lens awareness, easier adaptation,

lower risk of lens loss and a faster reduction in refractive

error compared to daytime wear [5]. Also, the patient

benefits from the freedom of having to wear optical

correction during the day which may interfere with sports

and recreational activities.

The major drawback of overnight wear ortho-k is the

potentially higher risk of corneal ulceration [6–10]. In many

shed by Elsevier Ltd. All rights reserved.

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2818

Asian countries, where myopia has a high prevalence, ortho-

k is mainly prescribed for slowing myopic progression in

children, and in most cases, overnight therapy is used. The

Internet is replete with unsubstantiated claims regarding the

efficacy of the procedure and this, unfortunately, is the most

common source of information for patients and parents

interested in the treatment for their children. This can lead to

unrealistic expectations and inappropriate or misleading

information which can lead to unhappy patients and/or

serious complications. A patient may claim compensation if

the practitioner makes unsubstantiated statements which

result in harm, as this may constitute negligence, or if the

practitioner is unable to provide reasonable care and skill in

diagnosis, advice and treatment resulting in injury to the

patient [1].

Guidelines have been established for silicone hydrogel

contact lenses for continuous wear [11]. In view of the

increasing popularity of overnight ortho-k, where children

may be involved, there is a need to develop guidelines for

this specialized treatment for the ortho-k practitioners [1].

Therefore, this paper aims to provide guidance for

practitioners on the standards required for competent

clinical practice in ortho-k. The authors also see the paper

as a means of initiating discussion between practitioners so

that a universally acceptable code of practice can be adopted

internationally.

2. Clinical setup

In the early days of revived interest in ortho-k in the late

20th century, there was little or no structured education

available. Practitioners had to educate themselves via trial

and error, or apprenticeship with a colleague experienced in

the procedure. However, ortho-k practice has since evolved

rapidly with improvements in the technique, including

higher Dk lens materials, advanced lens designs and corneal

topography for monitoring corneal shape changes. There has

also been a concomitant increase in the amount of published

scientific research on the effects and limitations of the

procedure, and specialized education programs developed in

order to raise the standard of practice.

Practitioners who wish to undertake ortho-k practice

should therefore attain the required educational standards

and equip their clinic properly prior to fitting patients. This is

already mandatory in the USA, where practitioners cannot

access supply of lenses until they have been certified to FDA

standards. The authors of this article firmly believe that pre-

certification, prior to supply, should be the standard for

ortho-k practice, so as to safeguard the interests of all

stakeholders. To that effect, an ortho-k course, organized by

the School of Optometry of The Hong Kong Polytechnic

University, has been established and is running annually at

the local level for practitioners in Hong Kong, providing

certification for individuals who successfully complete the

course.

2.1. Practitioners’ education in the fundamentals of

ortho-k practice

The most important preparation prior to ortho-k practice

is for practitioners to attain a comprehensive knowledge of

the underlying science of the process, including the pros and

cons, the risks and benefits, how to fit, assess and manage

ortho-k patients, and issues relating to aftercare. Practi-

tioners will also need to continue to update their education as

new information comes to light. In fact there is a legal

obligation to do so, as clarified by case law [12].

Practitioners must update their knowledge and ensure that

practice does not become obsolete or outdated. This can be

achieved via continuing education, including lectures,

workshops, conferences, reading journals and from com-

munication/sharing with peers. As stated in White and Cho

[1], in legal terms, the practitioner would not be able to

justify a lack of training for any shortcomings arising out of

practice, nor argue that ignorance of a new treatment, e.g.

ortho-k and its consequences, resulted in the adverse

outcome. Practitioners have a legal obligation to keep pace

with advancement should they decide to extend their

practice to envelop ortho-k practice. What is also clear from

case law, in common law jurisdictions, is that inexperience is

no defense in terms of negligence claims in the civil courts

[13]. Therefore, if one is not competent to practice

independently, due to lack of experience, then adequate

supervision is a must.

2.2. Minimum clinical instrumentation

There is of course the need to equip their practice with

appropriate instruments and/trial lens set(s), apart from the

basic instrumentation required for contact lens practice (slit

lamp, etc.). The importance of the corneal topographer

cannot be over-emphasized, and it should be considered

mandatory for a practitioner to not only own one, but also to

be conversant in reading and understanding the information

generated by it. Topographical data is used to design the lens

parameters and diagnose both the optimal and sub-optimal

effects of the lens on corneal shape. It is an important tool to

aid the practitioners to monitor and manage their patients

properly and adequately.

The practitioner should be aware of the features of the

instrument that make it suitable for ortho-k practice. These

include:

1. A

high degree of accuracy and repeatability.

2. S

tatistical analysis of repeated readings of apical radius

and eccentricity or elevation.

3. A

xial, tangential, and refractive power and curvature

maps.

4. A

‘‘difference’’ or subtractive map function.

5. P

upil recognition.

6. A

large area of corneal coverage with minimal

interpolation.

& Anterior Eye 31 (2008) 17–28 19

As stated previously, the accepted standard for instru-

mentation for ortho-k is ownership and use of a corneal

topographer.

Maldonado-Codina et al. [14] have shown that the use of

a corneal topographer, to design the lens and monitor the

results, is a distinct advantage. Other worthwhile equipment

would include a radiuscope for checking the accuracy of the

lens manufacture and a microscope for lens inspection.

2.3. Trial lens sets1

Various manufacturers supply trial lens sets so that the

practitioner can assess the corneal response to the lens prior

to proceeding fully with a course of treatment. Undoubtedly,

more than one common practice may exist among different

practitioners with different pros and cons. In the case of trial

lens sets, practitioners may choose to have a partial or full

set. Where some practitioners may choose not to use any

trial set, but to send patient data to the laboratory or to

directly order lenses via lens fitting software, the first lens

ordered for the patient will serve as the trial lens and will be

kept by the patient if the ortho-k results are good. It is

essential that all trial lenses are made from the highest Dk

material available, as low Dk material will not be suitable for

overnight trials. Maldonado-Codina et al. [14] have shown

that the use of trial lenses instead of empirical prescribing

can lead to a reduction in the number of lenses required as

well as the resultant saving in chair time.

Trial lenses can be stored either wet or dry. If stored dry,

the lenses should be carefully cleaned with a recognized

RGP cleaning agent, rinsed with saline and then dried prior

to placement in the holder. The lens holder or case should

also be cleaned regularly. If stored wet, the same rules apply,

but care must be taken to replace the storage solution at

regular intervals, and to check the lens container for biofilm

build-up. Lenses should also be checked regularly for

scratches (slit lamp microscope) and warpage (radiuscope).

2.4. Trial fitting

What is the adequate settling time for trial ortho-k fitting?

There are variations among practitioners. Some practitioners

do not keep trial lenses and order the first trial lenses by

sending relevant ocular or lens data (either the K readings or

the suggested lens parameters by lens fitting software) to the

laboratory. After the lenses are received, ortho-k treatment

for the patient commences with the very first pair of lenses

tried. For empirical fitting, usually the only corneal data

supplied to the laboratory are the K readings and it is

reported that empirical lens fitting will not lead to a high

first-fit success rate [14]. Also, the effects of the lens on the

cornea with respect to physiological response are unknown

prior to the commencement of the treatment, that is, a patient

may start on a course of treatment when it is inappropriate.

P. Cho et al. / Contact Lens

1 Note that in the UK, there are special and specific requirements for

cleaning trial lenses.

Some practitioners allow a couple of hours of settling

time, e.g. the patient is fitted with a pair of trial lenses and

asked to wear them for a specified period in the daytime and

then return for evaluation to determine if the lenses are

acceptable. When the patient returns, lens fitting (fluorescein

pattern and lens movement) is evaluated, and corneal

topographical changes are determined. The prescription lens

design is then determined from the results. Others allow the

patient to take the trial lenses home to wear overnight and to

return early the next morning to determine the lens fitting

and corneal topographical change. The results from this are

then used to determine whether further trials are required to

optimize the results or whether the final lens parameters can

be calculated and the lenses ordered. This method is the most

scientifically valid for the following reasons:

1. S

ignificant change in lens fit can occur as short as 10 min

of lens wear, that is, the validity of the observation of the

second trial lens can be affected by the changes induced

by the first trial lens [15].

2. A

short (1–4 h) open eye trial wear period may give clues

on refractive and visual response but cannot give the

same outcome as a full overnight trial of 8 h [15].

3. O

vernight ortho-k involves closed eye wear of the lenses

and not open-eye wear, where the effects of lid forces and

blinking can have an effect on lens centration.

4. C

losed-eye trial would determine ocular response to

overnight ortho-k.

Therefore, overnight trial is the preferred standard of lens

fitting. It is the only valid means of determining the

centration of the lens and the physiological suitability for the

treatment.

2.5. Appropriate charges for ortho-k treatment

Ortho-k requires practitioners to be diligent and vigilant.

Regular and frequent aftercare to monitor corneal changes is

essential. This is particularly important if children are

involved. It is therefore necessary for practitioners to take

the increased chair time into account when deciding on the

appropriate professional fee level. Fees charged for ortho-k

practice vary from one practice to the next. The important

issue here is that the fee structure is transparent and that any

patient agreeing to undergo a course of treatment using

ortho-k lenses is fully aware of the short- and long-term

costs of the treatment. There must be no hidden costs or

misrepresentation, as this could impact negatively on the

validity of the patient’s consent or, if applicable, on the

nature of the contract for services provided. There is a legal

responsibility to communicate sufficiently with patients so

that they are able to make informed decisions. Any

information which could potentially influence the patient’s

decision to undergo or forego a treatment or examination

should be disclosed. One’s duty to disclose also includes a

thorough and accurate representation of the costs. In the

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2820

Australian case of Rogers vs Whittaker [16], the judgment

determined that:

‘‘There is a fundamental difference between, on the one

hand, diagnosis and treatment and, on the other hand, the

provision of advice or information to the patient . . . Because

the choice to be made calls for a decision by the patient on

information known to the medical practitioner but not to the

patient, it would be illogical to hold that the amount of

information to be provided by the medical practitioner can

be determined from the perspective of the practitioner alone

or, for that matter, of the medical profession.’’ [17]

The same rules apply to the optometry profession and

patients must be duly informed about costs. How this

information is disclosed may vary, as some practitioners

may choose to offer a package price, including the first pair

of lenses that fit satisfactorily and a year of aftercare

consultations, whereas others may choose to charge their

patient per pair of lenses used, and a separate charge for

aftercare. Provided the costs are transparent, and the patient

is aware of these, then there should be no legal dilemma.

Ortho-k patients will continue to require regular and

frequent aftercare for as long as they continue to use

ortho-k lenses and patients should be made aware of this

from the outset.

2.6. Information and consent forms

In contact lens wear, ortho-k is not daily wear, nor is it

extended wear. However, it does involve overnight wear and,

though the risks involved in ortho-k are not fully understood,

it can be argued that it is expected to increase the risk over

daily wear contact lenses [18]. Although the Dk/t of lens

material used is high, it is still below the amount estimated

by Harvitt and Bonanno [19] to deliver adequate oxygen to

the cornea to avoid hypoxia under closed eye conditions. It is

therefore important for prudent practitioners to provide

adequate information to the patients before (Information

Table 1

Example of written advice on the pros and cons of ortho-k lens wear

Pros Cons

In successful overnight wear, good vision can usually be maintained

throughout the day after lens removal.

Ortho

gradu

Night therapy brings convenience to those who do sports or who

do not like to wear conventional contact lenses or spectacles

during the day.

Ortho

lenses

safe t

Our recent research has shown the treatment to be effective in

slowing myopic progression in children.

Due t

comp

On average, ortho-k can usually reduce myopia of 4.00D

within two weeks. However, individual variation does exist.

Some

corne

depen

Complications associated with conventional contact lens wear,

such as dryness and irritation from dust can be avoided.

Non-c

red ey

detec

The treatment is reversible and can be stopped anytime.

The eyes will soon resume their normal condition thereafter.

Treat

able t

Durin

sheets and Consent forms) and after commencing the

treatment (Education materials and advice).

2.6.1. Information sheets

In the case of children, before the patients and their

parents join the treatment, information about the treatment,

the pros and cons of ortho-k, potential and foreseeable risks

associated with ortho-k lens wear, and the alternatives

available, should be given. Table 1 is an example of written

advice on the pros and cons of ortho-k lens wear. The

information should not only point out the practitioner’s duty

of care to the patient and the charging system but also the

patient’s responsibilities with respect to lens care, main-

tenance and aftercare visits. An example of an information

sheet is shown in Fig. 1. Most importantly, the patient must

be given a ‘cooling–off’ period where they are encouraged

to think about the information they have been given, and

have the ability to seek clarification [1]. Only then should the

treatment commence.

2.6.2. Consent forms

Consent forms are important but are frequently over-

looked or underused. An example of a consent form is shown

in Fig. 2. The practitioners should also be clear about the

legal age of children who may sign the consent form.

Children of 16 years of age have reached the age of majority

in terms of setting their own health care course, as

determined by section 8 of the Family law Reform Act

1969 in England and Wales, and hence may legally consent

to treatment or examination without the parent/guardian

being informed. For children/minors below the age of 16

years, the parents should normally be involved in the

decision-making process and decisions will be made in the

child’s best interests after assessing the potential risks and

benefits. The same age criteria apply in Australia. It is

prudent to involve both the child and parent in the decision-

making process at the consent stage prior to ortho-k

treatment, especially with respect to mature minors, i.e.

-k is NOT a CURE for myopia. The treatment effect will wear off

ally after stopping lens wear.

-k lenses require more time to fit compared to conventional contact

. Aftercare consultations are more frequent to ensure effective and

reatment.

o changes in ocular environment under close eye condition, the risk of

lication is relatively higher than day wear regime.

contact lens-related problems, such as solution sensitivity, infection or

al epithelial trauma may occur, though the risk of complication is very

dent on compliance.

ompliance or poor compliance can result in significant corneal abrasion,

e and discomfort. Corneal ulceration may result if the condition is not

ted earlier or left untreated.

ment effect may vary and is patient dependent. Some patients may not be

o achieve the desired effect.

g the course of treatment, temporary spectacles may be needed.

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–28 21

Fig. 1. Example of information sheet.

those of 14–15 years of age. It may also be prudent to have

the mature minor, as well as the parent, sign the consent form

as a means of documentary evidence, although there is no

legal requirement for this to be done. It should also be noted

that some children under the age of 16 years may be ‘Gillick

competent’, meaning that if they have sufficient maturity

and understanding of their own health needs then they may

be permitted to consent without parental involvement [20].

However, with respect to ortho-k, it is highly unlikely that

such a scenario would arise but, if it did, the practitioner

should try to persuade the child to inform the parents or to

allow the practitioner to do so.

Furthermore, during the course of treatment practitioners

should note that legally, every time there is a significant

modification to the management or treatment protocol, e.g. a

new pair of lenses with amended parameters, patient consent

may also need to be re-addressed or re-visited. Hence, it is

important that practitioners are not over-zealous in their

promise of what ortho-k can achieve for their patients and

certainly they should avoid making claims which are

misleading.

2.6.3. Education materials and advice

Ortho-k involves some special procedures that are not

frequently encountered in conventional contact lens

practice. For example, lens binding is a common occurrence

in ortho-k lens wear, and it is therefore essential that the

patients know how to deal with this problem and remove the

lenses properly. The use of a lens suction holder is also

common among ortho-k patients, and they must therefore be

properly taught how to use the device safely and how to care

for this accessory. However, research studies have shown the

suction holder to be one of the most frequently and severely

contaminated items used by ortho-k children [21,22].

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2822

Fig. 2. Example of consent form.

Practitioners should therefore consider avoiding the

prescription of suction holders and teach children how to

remove their lenses by blinking or manipulation with their

fingers.

Leaflets or handouts on how to remove a bound lens

properly, how to use the suction holder safely, and how to

care for the lens and lens accessories would be useful for

distribution to the patients or their parents/guardians. It is

not advisable to try to incorporate all necessary information,

including those previously mentioned, in the consent form. It

is advisable to have them in separate handouts for

distribution to patients for reference.

2.6.4. Communication with patients

It would not be professional to simply distribute

instructions/advice or forms for patients to read by

themselves. A diligent practitioner needs to go through the

forms/instructions/advice to ensure that the patient has

understood the content and to allow the patient the

opportunity to ask questions. Again, this can reflect on the

validity of the consent, as patients must be informed in terms

they may readily understand and having time to digest the

contents of documentary information is an important

consideration. As mentioned earlier, it is important that

patients are clear about the pros and cons of ortho-k, and the

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–28 23

alternatives afforded to them. Practitioners should not allow

potential refusal of treatment to stand in the way of properly

informing patients, as patients must be able to make informed

decisions. Well-informed patients are more likely to comply

and are less likely to encounter problems. The important thing

is for practitioners to establish good rapport with their

patients. Having gone through the forms and handouts with

the patients, it is also important that the practitioners

document these actions in the patient’s file, or such

documentation may be indicated by a clause in the consent

form. This will minimize the chance of practitioners

forgetting to provide any set of instructions to the patients

and also be protective in civil cases when the practitioner and

patient disagree over the information provided. The need to

document has been clearly stated in Chester vs Afshar [23], a

case where there was a conflict of recollection between the

parties about what exactly the patient had been told. In this

case the defendant practitioner had made no notes about the

information provided and failed to convince the trial judge

that he had provided sufficient information. This typifies the

need to keep detailed contemporaneous notes on the patient’s

record of information received, especially about risks of

treatment. Disclosure of risks, pros and cons, and limitations

of ortho-k practice may be in written, verbal or video format.

All formats may be appropriate or reasonable, depending on

the circumstances at the time, and provided that the patient

understands what is being communicated. However, the

patient must be afforded the opportunity to ask questions and

to seek clarification on unclear issues. Therefore, face-to-face

appointments or telephone discussions, at least, should be

arranged to provide the patient the opportunity to do this.

Apart from oral and written advice and instructions, on-site

demonstration on how to care for the lenses is also important.

The importance of compliance cannot be over-emphasized

[24], and showing relevant examples of good compliance in

the office would be a good start. Special emphasis should be

placed on the care of lens accessories, particularly the lens

case and lens suction holder (if prescribed), as these items

have been identified to be the most frequently and severely

contaminated items in ortho-k [21,22]. Reviewing cleaning

and disinfecting procedures for lenses and accessories at

every aftercare visit would be prudent and essential as it has

been shown that most patients forget after a while. To ensure

that patients replace their lens case and suction holder

regularly, practitioners may consider getting patients to bring

these items back in exchange for new ones, as it has also been

shown that patients tend to forget to replace them [21,22].

Patients should also be reminded not to store accessories in

bathrooms or toilets. The standard of practice should therefore

consist of written and verbal communication with the patient

of the relevant risks and benefits of the procedure and the costs

associated with it, both initial and long-term.

Since ortho-k lenses are worn at night, it is important for

practitioners to provide a telephone number for their patients

in case of emergency. The telephone number may be written

or typed on a card which the patient can access easily, and

should not be buried in one of the information or instruction

handouts.

2.7. Consultation forms

As mentioned earlier, it is important for practitioners to be

meticulous in the documentation of the management of ortho-

k patients [23]. To minimize inadequate record-keeping, the

conventional contact lens record forms may be modified to

include checklists of essential assessments for each type of

consultation for ortho-k patients. An example of this is

presented in Appendix A (aftercare form). These checklists

will also serve as evidence of appropriate management and

care in case of a lawsuit. Should a legal case arise, it would be

the practitioner’s word against the patient’s, and any such

documentation (including consent form and information

handouts) would have greater credence and would lend

weight to the practitioner’s case.

The standard of care would therefore require specific and

comprehensive consultation documentation.

2.8. Properly educate supporting staff

It is important that supporting staff should be educated to

handle ortho-k queries. It is vital that staff have an accurate

understanding of what is involved in ortho-k. They should

not make over-zealous statements nor should they provide

misleading or negative comments. It would be advisable to

draft a list of frequently asked questions and the appropriate

answers.

The supporting staff should also be educated properly to

handle emergency calls.

If they are involved with insertion and removal, it is

important to keep a check on them, e.g. regular reviews

(unannounced of course) may be necessary to ensure a

quality service. They should also be educated on the

importance of compliance and proper care procedures.

Some practitioners will save the chair time by allowing

the supporting staff to teach the lens handling techniques. In

that case, the supporting staff should be properly trained by

the practitioners prior to handling a case. They should also

be educated and familiar with all the information to be

delivered to the patients. It is advisable that after the patients

can successfully handle the lenses, practitioners should

confirm their competency before dismissing the patients.

3. Clinical pearls in ortho-k practice

Some simple clinical pearls that can act as a guide to ‘best

practice’ in ortho-k are listed below.

3.1. Select patients carefully

In ortho-k practice, as in routine cases, it is prudent to

select patients carefully. Practitioners are well advised to

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2824

avoid patients with unrealistic expectations and, where

children are involved, avoid taking on child patients whose

parents cannot commit time and effort in monitoring lens

usage and care, or bring their children in for aftercare

consultations.

At what age should children be fitted? This question is

frequently asked by both practitioners and parents. There is no

norm. Some practitioners do not fit children, some practi-

tioners fit children over 7 years old, and some practitioners fit

children as young as 5 years old [25]. The decision is basically

up to the practitioners. The important issues are that (1)

parents are clearly and properly informed and are supportive,

not coerced and/or misled, and (2) the practitioners fit the

children because they see the need and are prepared to take

diligent and vigilant care of the children. In cases where the

child refuses to undergo the treatment, but the parents are

keen, it would be prudent to forego the treatment, as there is an

increased risk that the child will not be compliant, hence

increasing their exposure to risk. Furthermore, coercion from

the parent or practitioner to persuade the child to undergo the

ortho-k treatment would also violate the criteria for voluntary

consent and hence vitiate the consent.

Also, the child’s medical history MUST be taken into

account. Does the child suffer from any general medical

condition where their immune system may be compromised?

Is the child taking any medication that may interfere with their

ability to safely wear contact lenses (e.g. Roaccutane), or do

they suffer from any chronic general or mental health issue?

What is the standard of living of the patient, and how far away

from help are they if a problem arises? What is their general

environment like? Children have immaturely developed

immune systems, so the practitioner must be careful in

assessing the challenge to that system that the overnight wear

of contact lenses would invoke.

Children/minors are a particularly vulnerable group of

patients who may lack capacity to consent to treatment, so it

is vital that advice provided for parents/guardians is clear

and detailed so that they can safeguard the interests of their

children/wards. The parent/guardian must accept the

responsibility to help minimize the risks associated with

the treatment and be able to note early warning signs of

problems which may arise. They must also be able to take

appropriate action whenever necessary, but can only do so if

properly informed by the practitioner.

3.2. Information and consent form + verbal advice

As mentioned earlier, it is important that the patient is

adequately informed, and given a chance to ask questions

about the treatment on a regular basis. Failure to do so may

expose the practitioner to accusations of breach of duty and

carelessness, which may constitute negligence if the patient

suffers harm. Ortho-k patients will undertake a treatment

with known and foreseeable risks, so the practitioner has a

duty to provide reasonable aftercare, which includes regular

monitoring of the patient’s progress and updates on

information to ensure that the best interests of the patient

are assured. Consequently, it is highly advisable that patients

are provided with an emergency contact number, especially

as lens wear usually takes place after normal office hours.

3.3. Delivery

Patients (or parents if child cannot handle this procedure)

should be taught how to insert and remove lenses, and should

not be allowed to leave with the lenses until they have shown

that they can perform these tasks properly. They should be

taught to remove their lenses by the standard technique, with

the procedures being the same as for RGP lenses. However,

in view of the significant problem with lens binding, it might

be prudent to advise removal of lenses after instillation of a

drop of lubricant.

Parents and patients should be given the name of a proper

anti-bacterial hand wash that they can procure from the

pharmacy, and advised about the absolute importance of

hand washing prior to lens insertion and removal. Written

instructions are also essential. The patient should also be

directed to the location of the closest emergency eye centre

should it be needed.

The use of a suction holder to aid insertion and removal

should be avoided to prevent dependency on the suction

holder. It has also been reported [21,22] that patients tend to

forget about proper care of accessories, and a suction holder

is one of the most heavily contaminated items in contact lens

wear. However, if for whatever reason, it has to be

prescribed, careful instructions, written and oral, should

be given to ensure proper use and care of this accessory.

Other advice, applicable to general contact lens wear,

about abnormal and normal symptoms that may occur

should be given, and the schedule of aftercare explained (see

Section 3.4). The wearing schedule will be determined for

each individual in the following visits. It has been reported

that some patients only need to wear the lenses every second

night, but this cannot be used as a general rule, so the optimal

wearing schedule must be determined for the individual

patient. Some practitioners ask patients to stop wearing the

lenses during the weekend so as to rest but there is no

scientific evidence to support this argument. Oedema/

staining problems, if any, will not be resolved by asking a

patient to rest one night during the week.

3.4. Schedule of aftercare (standard of ortho-k practice)

Unlike conventional contact lens wear, an aftercare

schedule for ortho-k patients is more intensive especially

during the first year, and it is essential that patients,

particularly children, return for the scheduled aftercare to

minimize complications and to enhance compliance. We

recommend the schedule presented in Table 2. As discussed

earlier, since overnight wear is involved, it is important that

the patient returns early the next morning, after the first

overnight lens wear, to check for any signs of oedema.

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–28 25

Table 2

Recommended standard of practice in orthokeratology

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2826

Table 3

Daily cleaning and weekly disinfection of lens accessories

Daily cleaning

Discard the old solution in the lens case

Add a few drops of daily cleaner or non-moisturizing liquid soap.

Clean the lens accessories with a small soft brush (e.g. a soft-

head toothbrush). Pay attention to the wells, the rims and the

gaps between the wells of the lens case

Rinse with tap water. Air dry or wipe dry with clean paper towel. Store

in cool, dry place. Never put a wet suction holder back to its container

Always rinse with saline/MPS before use

Weekly disinfection

After cleaning, place the accessories in a container, and pour in boiling

water to cover all items

Put cover on and leave them to soak for 10 min

3.5. First aftercare visit

The first aftercare appointment after a delivery (of every

new pair of lenses) should happen early the next morning,

within two hours after awakening, with the lenses in situ.

This allows the practitioner to check for corneal oedema if

present. Although the Dk/t of RGP material used in ortho-k

is high, there are people whose corneas have higher oxygen

demand, and it is not possible to identify these individuals.

So no matter how high the Dk of the lenses, it is still prudent

and necessary to check the next morning to ensure that no

significant oedema or central corneal staining has occurred.

The routine consists of:

Take out the accessories. Air dry or wipe with clean paper towel

1. S

litlamp examination of the lens on the eye to determine

the presence of binding.

2. S

litlamp examination of the cornea for signs of oedema

(e.g. striae and folds) and for staining.

3. O

ver-refraction to serve as a baseline for determining any

increase in myopia.

4. R

emoval of the lens by the patient to check the

competency in lens handling.

5. U

naided VA and refraction to determine the visual

outcomes.

6. C

orneal topography to determine the centration of the

effect and the treatment zone diameter.

There is an absolute necessity to assess the presence and

extent of central corneal staining early in the morning. If

significant (�Grade 2 CCLRU Scale), then clinical action

must be taken since the central cornea is significantly

compromised and may increase the risk of microbial

keratitis. If the patient was not assessed until later in the day,

any signs of corneal oedema or significant central corneal

staining may have resolved, and the practitioner will have

missed these significant signs, which may lead to serious

clinical complications. The standard of practice therefore

requires some aftercare consultations (beside the first one) to

be performed in the morning, within 2 h of lens removal (see

Table 2).

At this aftercare visit, advice on lens care and

maintenance need to be reiterated and reinforced. Care of

lenses and lens accessories cannot be overemphasized, and it

is prudent to spend adequate time going through the

procedures diligently. Improper or inadequate care of

accessories has been shown to be the main cause of

microbial contamination, so it is important for the

practitioner to stress the need for daily cleaning and weekly

disinfection. These procedures are presented in Table 3.

3.6. Subsequent aftercare

After the first aftercare visit, depending on the outcome of

the visit, a subsequent visit is usually arranged 1 week after

the first overnight wear. If indicated, it may be arranged on

the next day or 2–3 days later. The recommended aftercare

visit schedule is shown in Table 2. After the treatment has

settled satisfactorily, regular aftercare visits, once every 3

months in the first year and every 6 months thereafter should

be recommended. During the subsequent aftercare, it is

important to record unaided VA, aided VA, the residual

refractive error, biomicroscopic findings, and to take corneal

topographic maps. The use of a modified aftercare form, e.g.

with checklist of tests to perform, would be useful. It is

important not to underestimate the importance of aftercare

visits, particularly corneal changes, as it has been reported

that subtle corneal changes can occur with ortho-k [26–31].

It is also important to review care procedures and the

commitment of the parents/patients at these visits, and re-

educate them if necessary. Over time, parents/patients tend

to become complacent, and reviews/re-education will serve

to decrease the level of non-compliance. To avoid forgetting

and for documentation purposes, we suggest the use of a

checklist incorporated in the aftercare form as shown in

Fig. 3. If necessary, patients can be asked to sign next to the

checklist.

3.7. Communication with parents/patients

Ensuring willingness for commitment from both parents

and children, establishing a good rapport, and gaining the

trust of patients/parents, are very important. These

contribute significantly to the success of the treatment,

and decrease the chance of complications due to non-

compliance, and the unhappy aftermath from poor corneal

response or unrealistic expectations.

3.8. Recall of patients for aftercare

In conventional contact lens wear, in particular soft

contact lens wear, patients are notoriously bad at returning

for aftercare consultations, especially after a few months of

lens wear. In ortho-k, the risk of serious complications

associated with lens wear is higher due to overnight lens

wear, so it is important to ensure that patients return for

scheduled aftercare consultations. It is also suggested that

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–28 27

Fig. 3. Example of checklists incorporated in the consultation forms for easy reviewing and recording patients’ compliance.

the cost of the treatment should encompass the cost of all the

aftercare consultations for a period of time, e.g. for a year.

Patients should not be left to decide whether or not they

come, and it is advisable for practitioners to ensure that they

do return for aftercare. What if patients failed to show up in

spite of repeated phone calls? We suggest that at least three

phone calls should be made and documented, and if the

patient still fails to show, a registered letter should be sent to

the patient. If this is done, then the practitioner has taken

reasonable steps to fulfill his/her duty and any harm resulting

from future use of the lenses can be defended by citing the

patient’s non-compliance. Under such circumstances, a

court of law is likely to agree that the patient has been at fault

as a consequence of contributory negligence, as the patient

has failed to follow clinical advice.

4. Conclusion

Overnight ortho-k is gaining popularity and the interested

practitioners need to be well prepared. Practitioners need to

equip themselves well to practice ortho-k and diligent and

vigilant care is essential. There is still a lot we do not

understand about ortho-k, and rightly a lot of research is still

going on to seek further understanding and to increase the

safety of ortho-k practice. It is therefore important that

practitioners keep abreast of latest developments in ortho-k

and continue to improve their ortho-k practice to provide

quality service to their patients.

Appendix A. Supplementary data

Supplementary data associated with this article can

be found, in the online version, at doi:10.1016/j.clae.

2007.07.003.

References

[1] White P, Cho P. Legal issues in contact lens practice with special

reference to the practice of orthokeratology. Ophthalmic Physiol Opt

2003;23:151–61.

[2] Jacobson J. Orthokeratology: the global perspective. In: Global ortho-

keratology symposium 2005; 2005.

[3] Cho P, Cheung SW, Edwards M. Longitudinal orthokeratology

research in children (LORIC) in Hong Kong: A pilot study on

refractive changes and myopic control. Curr Eye Res 2005;30:71–80.

[4] Walline J. CRAYON study. In: AOCLE workshop 2006; 2006.

[5] Grant S. Orthokeratology night therapy and retention. Contacto

1995;35:30–3.

[6] Chen KH, Kuang TM, Hsu WM. Serratia Marcescens corneal ulcer as

a complication of orthokeratology. Am J Ophthalmol 2001;132:257–8.

[7] Gupta N, Weinreb RN. Filtering bleb infection as a complication of

orthokeratology. Arch Ophthalmol 1997;115:1076.

[8] Lu L, Zou L, Wang R. Orthokeratology induced infective corneal

ulcer. Zhonghua Yan Ke Za Zhi 2001;37:443–6.

[9] Hutchinson K, Apel A. Infectious keratitis in orthokeratology. Clin

Exp Ophthalmol 2002;30:49–51.

[10] Watt K, Swarbrick HA. Microbial keratitis in overnight orthokeratol-

ogy: review of the first 50 cases. Eye Contact Lens 2005;31:201–8.

[11] Brennan NA, Coles C, Jaworski A, Rosario D. Proposed practice

guidelines for continuous contact lens wear. Clin Exp Optom

2001;84:71–7.

[12] Roe vs Minister of Health. 2 All ER 131; 1954.

[13] Nettleship vs Weston. 3 All ER 591, CA; 1971.

[14] Maldonado-Codina C, Efron S, Morgan P, Hough T, Efron N. Empiri-

cal versus trial set fitting systems for accelerated orthokeratology. Eye

Contact Lens 2005;31:137–47.

[15] Sridharan R, Swarbrick H. Corneal response to short-term orthoker-

atology lens wear. Optom Vis Sci 2003;80:200–6.

[16] Rogers vs Whittaker. 4 Med LR 79 at 83; 1993.

[17] Mason JK, Laurie GT. Law and medical ethics. Oxford: Oxford

University Press; 2006. p. 403–4.

[18] Swarbrick H. Orthokeratology review and update. Clin Exp Optom

2006;89:124–43.

[19] Harvitt D, Bonanno JA. Re-evaluation of the oxygen diffusion model

for predicting minimum contact lens Dk/t values needed to avoid

corneal anoxia. Optom Vis Sci 1999;76:712–9.

[20] Gillick vs West Norfolk and Wisbech Area Health Authority; 1984.

[21] Boost MV, Cho P. Microbial flora of tears of orthokeratology patients,

and microbial contamination of contact lenses and contact lens

accessories. Optom Vis Sci 2005;82:451–8.

[22] Cheng CS, Cho P, Boost M. Microbial contamination of orthoker-

atology lens and lens accessories in young patients. In: The 12th

international congress of infectious diseases; 2006.

[23] Chester vs Afshar. EWCA Civ 724; 2002.

[24] Claydon BE, Efron N. Non-compliance in contact lens wear. Ophthal-

mic Physiol Opt 1994;14:356–64.

[25] Cho P, Cheung SW, Edwards MH, Fung J. An assessment of con-

secutively presenting orthokeratology patients in a Hong Kong based

private practice. Clin Exp Optom 2003;86:331–8.

[26] Cho P, Chui WS, Mountford J, Cheung SW. Corneal iron ring associated

with orthokeratology lens wear. Optom Vis Sci 2002;79:565–8.

P. Cho et al. / Contact Lens & Anterior Eye 31 (2008) 17–2828

[27] Rah MJ, Barr JT, Bailey MD. Corneal pigmentation in overnight

orthokeratology: a case series. Optometry 2002;73:425–34.

[28] Liang JB, Chou PI, Wu R, Lee YM. Corneal iron ring associated with

orthokeratology. J Cataract Refract Surg 2003;29:624–6.

[29] Hiraoka T, Furuya A, Matsumoto Y, Okamoto F, Kakita T, Oshika T.

Corneal iron ring formation associated with overnight orthokeratol-

ogy. Cornea 2004;23:S78–81.

[30] Cheung SW, Cho P, Cheung A. White lesion in the corneal pigmented

ring associated with orthokeratology. Ophthalmic Physiol Opt

2005;25:264–8.

[31] Cheung SW, Cho P, Bron AJ, Chui V, Chan B. Case report: the

occurrence of fibrillary lines in overnight orthokeratology. Ophthalmic

Physiol Opt 2006;26:525–31.